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    <title>Document</title>
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    <script>
        const p1  = new Promise((resolve,reject)=>{
            // 用定时器模拟一个异步函数
            console.log('请求a数据。。。。');
            //  throw new Error('出现错误了')
            try{
                setTimeout(()=>{
                  resolve('成功');
                // reject('cuo')
                console.log('获取a数据成功');
            },2000)
            }catch(e){
                reject(e)
            }
        });
        console.log('p1',p1);
        
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